Gas control electrical circuits which utilize an electromechanical relay to control the operation of a gas solenoid valve which, in turn, regulates the flow of gas to a burner are known in the prior art. Such circuits might utilize flame rectification techniques to provide the voltage required to actuate or to maintain actuation of the foregoing relay. Additionally, such circuits might incorporate a timing mechanism permitting the actuation of the relay for a predetermined period of time, and if ignition does not occur during this time period, causing the deactuation of the relay to prevent gas from accumulating within the system. Gas purging techniques might also be employed before and/or after the predetermined time period to prevent such gas accumulation.
These prior art circuits typically use silicon controlled rectifiers (SCR's) to control the electromechanical relay which controls the gas solenoid valve. Alternatively, the gas solenoid valve may be controlled directly by the SCR. Other circuit elements, such as bipolar or field effect transistors, are typically used to control the operation of the SCR. Thus, the resulting control circuits are relatively complex structurally and operationally, costly to produce, and present reliability problems due to their inherent complexity.
Because of the foregoing, it has become desirable to develop a simple, inexpensive, reliable electrical circuit for controlling the operation of a gas solenoid valve which regulates the flow of gas to a burner.